Blood sample collection assembly

Abstract: A blood sample collection assembly operable in a normal mode and convertible to a retraction mode, comprising: a first chamber (302) forming a hollow nozzle (306) located at the distal end of said first chamber and opening into the interior of said first chamber; a vacuum tube chamber (304) connected to said first chamber (302) and positioned substantially orthogonal to said first chamber, said vacuum tube chamber having an open end for receiving a vacuum tube (340); a needle carrier (308) carrying a first hollow needle (310) on the distel end thereof and carrying a second hollow needle (312) substantially orthogonal to said first hollow needle, said second hollow needle being in fluid communication with said first hollow needle, said second hollow needle extending into said vacuum chamber (304), said needle carrier being slidably mounted in said first chamber (302), said needle carrier being detachably engaged to said first chamber with the distal portion of said needle carrier being disposed within said nozzle (306) of said first chamber during the normal mode; and retraction means (324,326) for disengaging said needle carrier (308) from said first chamber (302) to switch the assembly from the normal mode to the retraction mode and for retracting said needle carrier into the first chamber such that said first needle (310) is concealed within said first chamber.

Description: Field of the Invention The present invention generally relates to blood sample collection assemblies in accordance with the preamble of claim 1. Background of the Invention A hypodermic needle entering into patient's body is invariably contaminated by the patient's blood and body fluids. Following use of the needle, the needle presents a risk to physicians, nurses and other health care personnel because the needle might transmit an infection or disease to such personnel if it were to accidently puncture them. Thus, health care personnel are in constant danger of contracting infections and diseases, some of which may be deadly. Other potential victims of accidental needle punctures include sanitation workers which later dispose of garbage containing the hypodermic needle. The disease which may be transmitted by a contaminated hypodermic needle include Immune Deficiency Virus, Hepatitis, Rabies, Kure, Encephalitis, and Arbor viruses. The outcome of contracting one of these diseases is often fatal because there are no known cures for any of these diseases. Often a needle puncture in a person's skin is so trivial that it remains unrecognized until the person becomes seriously ill. The problem of suffering accidental needle punctures is well recognized. As a result, enormous inventive effort has been devoted to concealing the sharp needle point of the hypodermic needles. Despite this effect, the prevalence and magnitude of needle prick-transmitted diseases is still high, as reflected in such recent articles as "Health Care" by Helene Cooper, Wall Street Journal (Nov. 25, 1992); The G.M.P. Letter (May 1992); Devices & Diagnostics Letter, Vol. 19, No. 19 (May 8, 1992); and FDA Medical Bulletin, Vol. 22, No.2 (Sept. 22, 1992). In order to avoid the transmittal of disease by needle punctures, efforts have been directed to preventing exposure of the sharp point of the hypodermic needle. One approach is to cap the needle following use. This approach, however presents a risk of danger because it involves placing the fingers directly opposite to the needle point. To help keep the fingers away from the needle point while capping the needle, needle caps provided with wide mouths or long handles have been developed by others. While the foregoing needle caps reduce the risk of suffering a needle prick, this approach still requires a person to place his/ her fingers near the needle and such finger placement is an active invitation to a needle prick. It cannot be over emphasized that even a single contaminated needle prick is unacceptable. Another approach to concealing hypodermic needles following use is to provide safe disposal containers. Such safety containers, however, do not solve the problem because needle pricks can and do occur even before the hypodermic needles reach their final disposal destination in the safety containers. Description of Related Art With respect to collecting blood samples using a double pointed hypodermic needle, approaches to protecting against needle punctures have been directed toward needle caps, safety disposal containers, and protective sleeves. The closest prior art is U.S. Patent No. 5,030,209 to Wanderer et al. This reference describes a double ended needle mounted on a syringe slideably connected to a coaxial tube. Advancement or retraction of the co-axial tube conceals the projecting end of the double ended needle. The holder includes an insert (12) for supporting the double ended needle. The insert has a tab which enters and slides into a slot located on a sleeve (50) of cylinder (14). The cylinder is co-axially located on the insert, which is freely movable and lockable at two positions within the cylinder. Locking is achieved by engaging tabs on the insert with the slots on the cylinder. Forward movement of the sleeve (50) shields the venipuncture needle. Other capping and sleeving mechanisms are also described. U.S. Patent No. 4,731,059 to Wanderer describes a two-piece protective shield (Fig. 6) to enclose the double ended needle for maintaining sterility and preventing accidental needle sticks. Also described is a slidable co-axial sleeve on a venipuncture needle (See Figs. 20 and 21). U.S. Patent No. 4,782,841 to Lopez discloses a venipuncture needle having a guard assembly consisting of a collar (80) and co-axially slidable and lockable guard (70). In a first position the venipuncture needle is exposed, while in a second position the guard is advanced and locked so as to conceal the venipuncture needle. U.S. Patent No. 4,819,426 to Haber discloses a shielded safety syringe (1) comprising an outer protective sleeve (2) having an open proximal end, a substantially closed distal end except for a central opening (6) to accommodate the distal venipuncture (44) end of the double ended needle, an inner spring biased cylindrical needle carrier (14) with open proximal end and closed distal end except for a central opening to accommodate the vaccutainer end covered by the protective sheath (18) of the double ended needle (8). Co-axially aligned with the needle carrier is a double ended hypodermic needle (8). Extending radially from opposite side of the needle carrier (14) are a position control button (20) and guide tab (22), adapted to be received in and slid through the axial guide channels (9) and (10) locked with detentes (12) and (13) of the outer sleeve (2). A helical compression spring (30) is received within the outer sleeve (2) and the needle carrier (14). The reciprocating action of the sleeve (2) and the needle carrier (14) permits a change in the axial length of the sleeve and the needle carrier. Advancing the sleeve conceals the venipuncture end of the needle. This action is aided by the spring but same can be done manually without a compression spring (30). U.S. Patent No. 4,819,659 to Sitar describes a unitary structure (14) consisting of tube holding section (16) and locking section (18). The needle guard (20) is located co-axially on the tube forming locking section (18) and lockably encloses the needle. Advancing the sheath forward enclosed the entire venipuncture needle section. U.S. Patent No. 4,887,998 to Martin discloses a tapering plastic cap (33) with an apical opening (39) and a compressed co-axial spring (27) is located at the base of a venipuncture needle (19). The needle projects through the opening (39). After using the needle, the latch (29) is released, recoiling the spring (27) and advancing the cap beyond the tip of the needle. The end of the needle abuts against a baH - (37) and is prevented from protruding through the end hole (39). U.S. Patent No. 4,927,019 to Haber et al. describes a sterile packaging for a double ended blood collection needle to solve the problem of needle sticks which occur during attachment of the needle to the barrel. Haber et al. does not address the issue of contaminated needle pricks caused by the puncturing needle. Disclosed is a needle sheath and sterility package comprising a lower needle cover (2) to surround and protect the distal end of a double ended hypodermic cannula (6) and an upper sleeve (4) to surround and protect the proximal end (8) of the cannula. The upper sleeve can be opened to permit the bore of the conventional hypodermic syringe to be received. U.S. Patent Nos. 5,000,167 and 5,188,119 to Sunderland describe a blood collection device (10) having a foldable one-piece molded housing (16 and Fig. 4A) enclosing a non-linear needle (24) with parallel ends (38 and 34) projecting in opposite directions proximally and distally. The distal end (38) is enclosed in a plastic tubular protective sheath (28) that is mounted on a shield assembly (27). The shield assembly is capable of reciprocal sliding action by displacing the finger assembly (30). A slot (40) on the tubular needle protective shield (28) permits retraction of the shield (28) at the angular portion of the needle. The protective shield is lockable at two positions (46 and 52). A rectangular hard case (56) encloses the proximal compartment while another tubular hard case (60) encloses, protects and maintains sterility of the distal needle and protective shield. Another similar embodiment is also described. U.S. Patent No. 5,002,536 to Thompson describes a conventional needle protector that has an inside diameter (36) smaller than the outside diameter (26) of the needle hub. Inside the protector are projections (44) which lock with the projections on the needle hub (22). The protector includes a wide conical mouth to prevent injury to fingers during the insertion of the needle inside the needle protector. U.S. Patent No. 5,069,669 to Kole discloses a finger guard (25) including a tubular element (26) of flexible needle puncture resistant material. The tubular element (26) has first (27) and second (28) circumferentially contiguous end sections joined by a plurality of longitudinally expanding circumferentially contiguous stripes (29) which project radially to form an umbrella like structure and protect against needle sticks when expanded. U.S. Patent No. 5,181,524 to Wanderer et al. discloses an extension of the interconnection between a double ended needle and a needle holder (Fig. 38-46) which permits a large girth holder to be employed without compromising the preferred needle entry angle. Other embodiments of the needle guard include telescoping guards (Figs 38 and 46) to shield the lengthy needles. Each guard is manipulated from the rear. An annular trough within the needle guard restrains the flow of contaminated liquids. These devices suffer from the drawbacks described above. In particular, needle caps and safety disposal containers do not provide adequate safety against needle punctures. Also, the devices which include protective sleeves are bulky, interfere with a person's grip and transmission of insertion force, disturb the insertion angle of the needle for penetration into the vein, and have the problem of sleeve dislodgment. Finally, coaxially-advancing needle protective devices have one or more of the previously discussed drawbacks, i.e., reduced functionality, unreliability, complexity of design, and high cost. Summary of the Invention A primary object of the present invention is to provide a blood sample collection assembly having a hypodermic needle which performs all the conventional functions of the hypodermic needle, and yet allows the hypodermic needle to be retracted and concealed in a barrel or chamber of the assembly following use. This objective is realized by providing a blood sample collection assembly according to claim 1. Advantageous embodiments are set forth in the depending claims. Another advantage of the present invention is to provide an assembly which includes a securely attached hypodermic needle and which promotes easy puncture of patient's skin and veins, and yet allows the hypodermic needle to be retracted and concealed in a barrel or chamber of the assembly in response to actuation of a retracting mechanism. Yet another advantage of the present invention is to provide an assembly which avoids inadvertent activation and premature retraction of the needle before or during the use of the assembly. Still another advantage of the present invention is to provide an assembly which irretrievably locks and immobilizes a retracted needle inside the barrel or chamber such that the retracted needle cannot be removed from the barrel unless it is intentionally broken and destroyed. Thus, the assembly is irreversibly safe. Another advantage of the present invention is to provide an assembly which permits the hypodermic needle to be retracted and concealed in a barrel or chamber of the assembly without the user positioning his or her fingers near the sharp point of the hypodermic needle. A further advantage of the present invention is to provide an assembly which is cost-effective and easy to manufacture. Brief Description of the Drawings Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: Fig. 1 is a longitudinal section of a blood sample collection assembly embodying the present invention; Fig. 2 is a longitudinal section of the blood sample collection assembly in Fig. 1 with the vacuum tube partially advanced within the vacuum tube chamber; Fig. 3 is a longitudinal section of the blood sample collection assembly in Fig. 1 with the vacuum tube completely advanced within the vacuum tube chamber so that a needle of the assembly pierces the rubber stopper of the vacuum tube; Fig. 4a is a side plan view, taken orthogonal to the longitudinal sections in Figs. 1 -3, of the blood sample collection assembly embodying the present invention; Fig. 4b is a top plan view of the blood sample collection assembly in Fig. 1; Fig. 4c is a longitudinal section of the blood sample collection assembly in Fig. 1 with the needle carrier and mounted needles being shown in the forward position (solid lines) and the retracted position (dotted lines); Fig. 5 is a longitudinal section of the blood sample collection assembly in Fig. 1 with the needle carrier and mounted needles in the retracted position; Fig. 6a is an exploded perspective view off the blood sample collection assembly in Fig. 1 showing that the external body is thermoformed from two polymeric constructions which are mirror images of one another; and Fig. 6b is a perspective view showing the manner of assembly of the blood sample collection assembly in Fig. 6a; Fig. 7 is an enlarged cross section of an over the needle catheter assembly not falling within the scope of the present invention. Fig. 8 is a section taken generally along line VIII-VIII in Fig. 7; Fig. 9 is a cross-section of the over-the-needle catheter assembly in Fig. 7 with the needle carrier and mounted needle in the retracted position; Fig 10 is a perspective view of a T-latch for retracting the needle carrier of the over-the-needle catheter assembly with the T-latch shown in the forward position; Fig. 11 is a fragmentary section taken generally along line XI-XI in Fig. 10; and Fig. 12 is a perspective view of a T-latch for retracting the needle carrier of the over-the-needle catheter assembly with the T-latch shown in the retracted position. While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. An embodiment of the present invention, illustrated in Figs. 1 -6b provides a blood sample collection assembly including an integral external body 300 forming a first needle chamber 302, a second needle chamber 303, and vacuum tube chamber 304. The axis of the first needle chamber 302 is orthogonal to the axis of the vacuum tube chamber 304. The first needle chamber 302 is a tubular or square hollow body having a hollow tapered conical nozzle 306 integrally connected to the distal end thereof. The nozzle 306 forms a locking female luer taper. The interior of the conical nozzle 306 communicates with the interior of the first needle chamber 302. A cylindrical needle carrier 308, having either a double-ended hypodermic needle with ninety degree bend or a pair of orthogonal hypodermic needles 310, 312 mounted therein, is disposed within the first needle chamber 302. The needle carrier 308 is displaceably interlocked to the first needle chamber 302 by a taper lock between the conically tapered portion 314 of the needle carrier 308 and the nozzle 306. The needle 310 protrudes from the distal end of the needle carrier 308 and is coaxial with the first needle chamber 302. Prior to using the blood sample collection assembly, the needle 310 is covered by a conventional protective cap (not shown) to prevent the sharp beveled point of the needle 310 from accidently puncturing someone. The needle 310 projects approximately one and one-quarter inches from the tapered portion 314 of the needle carrier 308. The other needle 312 is integrally connected to and mounted ninety degrees away from the needle 310. During normal use, the needle 312 is positioned along the axis of the vacuum tube chamber 304 and the needle 312 protrudes from a side arm 313 of the needle carrier 308 into the vacuum tube chamber 304 at its base 338. In one embodiment, the needle 312 is a metallic hypodermic needle capable of penetrating a rubber stopper of a conventional vacuum tube. Alternatively, the needle 312 may be composed of plastic capable of penetrating a rubber stopper but incapable of penetrating skin, thereby eliminating the need for the second needle chamber 303. Such a plastic needle is manufactured and distributed by Baxter International of Deerfield, Illinois. The use of the plastic needle reduces the possibility of accidental needle punctures by one-half. Since both of the needles 310, 312 are hollow, the interior of the needle 310 communicates with the interior of the needle 312 to form a continuous flow path between the needles. The needle 312 is covered by a self-sealing rubber cap 330 having an open end 332 and a closed end 334 (FIG. 6a). The rubber cap 330 is retained in place by a plastic retaining ring 336 mounted on the circumference of the needle 312 (FIG. 6a). As a vacuum tube 340 is inserted into the vacuum tube chamber 304, the rubber stopper 342 of the vacuum tube 340 depresses the cap 330 so that the needle 312 pierces both the closed end 334 of the cap 330 and the rubber stopper 342 (FIG. 3). This allows blood entering the needles 310, 312 to pass into the vacuum tube 340. As the vacuum tube 340 is removed from the vacuum tube chamber 304, the cap 330 springs back to its position covering the needle 312 so as to check the flow of blood exiting from the needle 312. Thus, the rubber cap 330 acts as a valve which is opened by inserting a vacuum tube 340 into the vacuum tube chamber 304 and which is closed by removing the vacuum tube 340 from the vacuum tube chamber 304. The vacuum tube 340 recited herein may be any glass or plastic tube or tubular stem of a flask that is closed by a rubber stopper and contains a vacuum. Following normal use of the blood sample collection assembly, the needle carrier 308 is retracted toward the proximal end of the first needle chamber 302, thereby causing the needle 312 to retract into the second needle chamber 303 (FIG. 5). The second needle chamber 303 is preferably a generally rectangular body which is narrow is one transverse direction and relatively wide in the other transverse direction (see FIGS. 6a-6b). The transverse dimensions are sufficiently wide to accommodate the width and length of the needle 312. The longitudinal dimension of the second needle chamber 303 is sufficiently long to accommodate the needle 312 when the needle carrier 308 is fully retracted within the first needle chamber 302. At the proximal end, the first needle chamber 302 forms a lid 316 having a circular lid aperture 318. Furthermore, an internal tube 320 is disposed within the first needle chamber 302, and the tube 320 is connected to a circular knob 322 via the lid aperture 318. Both the tube 320 and the circular knob 322 are coaxial with the first needle chamber 302, and rotation of the circular knob 322 relative to the first needle chamber 302 causes the tube 320 to rotate relative to the first needle chamber 302. The circular knob 322 preferably includes a textured longitudinal surface to permit the knob 322 to be easily gripped and rotated. The length of the internal tube 320 matches the internal longitudinal dimension of the first needle chamber 302 to prevent axial movement of the tube 320 relative to the first needle chamber 302. Moreover, the outer diameter of the internal tube 320 is slightly smaller than the inner diameter of the first needle chamber 302 to permit the internal tube 320 to rotate freely, yet stably, relative to the first needle chamber 302. Rotation of the internal tube 320 relative to the first needle chamber 302 causes the needle carrier 308 to move axially within the first needle chamber 302 from a forward position to a retracted position. In FIG. 4c, the forward position of the needle carrier 308 is depicted in solid lines, while the retracted position is depicted in dotted lines. Axial movement of the needle carrier 308 relative to the first needle chamber 302 is effected using a helical slot 324 in the circumferential wall of the internal tube 320 in conjunction with a longitudinal slot 326 in the wall of the first needle chamber 302. The helical slot 324 and longitudinal slot 326 are positioned such that the side arm 313 of the needle carrier 308 extends through both the distal end of the helical slot 324 and the distal end of the longitudinal slot 326 when the needle carrier 308 is in the forward position (FIG. 4a). Similarly, when the needle carrier 308 is in the retracted position, the side arm 313 extends through both the proximal end of the helical slot 324 and the proximal end of the longitudinal slot 326. From the foregoing arrangement, it can be seen that the distal end of the longitudinal slot 326 overlies the distal end of the helical slot 324 when the needle carrier 308 is in the forward position, and the proximal end of the longitudinal slot 326 overlies the proximal end of the helical slot 324 when the needle carrier 308 is in the retracted position. During retraction of the needle carrier 308, the first needle chamber 302 is held stationary while the internal tube 320 is rotated using the circular knob 322. While the internal tube 320 is being rotated, the needle carrier 308 is prevented from rotating with the internal tube 320 by virtue of the extension of the side arm 313 through the longitudinal slot 326 in the first needle chamber 302. Instead of rotating, the needle carrier 308 moves axially through the first needle chamber 302. More specifically, axial movement of the needle carrier 308 is controlled by the movement of the side arm 313 through the helical slot 324 in the rotating tube 320. As the side arm 313 moves through the helical slot 324, the side arm 313 cannot rotate or "swing" with the internal tube 320 because the side arm 313 is lodged in the longitudinal slot 326. Instead, the side arm 313 is forced to ascend the longitudinal slot 326 until the side arm 313 reaches the proximal end of the helical slot 324 (FIG. 5). At the proximal end of the helical slot 324, there is a detente 328 for engaging the ascending side arm 313, thereby locking the needle carrier 308 in the retracted position. To operate the blood sample collection assembly, the protective cap is removed, the blood sample collection site on the body of a patient is determined, and the skin is cleaned with an antiseptic solution. The needle 310 is then entered into the vein of the patient. To collect a blood sample, the vacuum tube 340 with the rubber stopper 342 is inserted into the vacuum tube chamber 304 (FIGS. 2-3 ). After the vacuum tube 340 is filled with the desired amount of blood, the vacuum tube 340 is removed from the vacuum tube chamber 304. Additional blood may be collected by inserting, filling, and removing additional vacuum tubes. The vacuum tube chamber 304 includes tabs 344 for providing leverage while pushing a vacuum tube over the point of the needle 312 to puncture the rubber stopper of the vacuum tube. While inserting a vacuum tube, the orthogonal orientation of the vacuum tube chamber 304 relative to the first needle chamber 302 compels that the vacuum tube be pushed into the vacuum tube chamber 304 in a direction toward a stabilizing hand, rather in the direction of the sharp point of the needle 310 located in the vein. Next, the needle 310 is withdrawn from the vein. The circular knob 322 is rotated until the needle carrier 308 is completely retracted with the side arm 313 locked in the detente 328 (FIG. 5). With the needle carrier 308 in the retracted position, the needle 310 is concealed by the first needle chamber 302 and the needle 312 is concealed by the second needle chamber 303. Finally, the blood sample collection assembly is discarded in its entirety. It can be seen from the foregoing description that the blood sample collection assembly avoids the situation of advancement of one sharp point of a double-pointed needle towards an operator while retraction of another point of the double-pointed needle is attempted. In particular, since the needle 312 is orthogonal to the needle 310, the side of the needle 312, instead of the point of the needle 312, is advanced toward an operator while the needle 310 is retracted into the first needle chamber 302. Moreover, both needles 310, 312 are retracted and concealed by operating a single mechanism, the circular knob 322. Due to the orthogonal orientation of the vacuum tube chamber 304 relative to the first needle chamber 302, insertion of a vacuum tube is accomplished by pushing the vacuum tube in the direction of a stabilizing hand of an operator, rather than in the direction of the needle in the vein. This reduces the possibility of imparting forward thrust on the needle in the vein which, in turn, minimizes the possibility of double puncturing the vein. Furthermore, the blood sample collection assembly is compact because the needle carrier 308 is retracted directly into the internal tube 320 itself. Because the needle carrier 308 retracts into the internal tube 320, the internal tube 320 need not extended beyond the proximal end of the first needle chamber 302 for needle retraction to occur. Thus, when discarded following use, blood sample collection assembly contributes minimally to the bulk of refuse. The blood sample collection assembly is also compact because, with the needles 310, 312 mounted orthogonal to one another, the length of the assembly is shorter than existing blood sample collection assemblies. Referring to FIGS. 6a-6b, the blood sample collection assembly is constructed by injection molding the entire assembly from organic polymers, preferably thermoplastics such as a polypropeline or ABS. To construct the needle chambers 302, 303 and the vacuum tube chamber 304, a polymeric sheet is thermoformed to represent a single piece, mirror image, isometric half of these elements. Next, the internal tube 320 with the mounted knob 322 and the needle carrier 308 with the mounted needles 310, 312 are positioned at the proper location on the thermoformed sheet, and the thermoformed sheet is folded and secured shut by interlocking detents on the contacting surfaces (Fig. 6b). For additional safety an ultrasonic or solvent bond is created at the areas of contact to maintain the integrity of the assembly. The assembly is sterilized by conventional means. Figs 7 -9 depict an OTN catheter assembly which does not fall within the scope of the present claims but which is included for reference purposes, the asssembly including an OTN catheter 400, a needle chamber 402, a flashback chamber 404, a needle carrier 406 with a hypodermic needle 408 mounted therein, a latch 410 connected to the needle carrier 406. In the preferred embodiment, the OTN catheter 400 is a polymeric catheter having a feathered tip 412 mounted thereto. The needle chamber 402 is a tubular or square body with a distal conical nozzle 414 and a proximal cover plate 416. The distal outer surface of the needle chamber 402 has prominent textured markings to permit a user to frictionally grip the chamber during insertion of the needle 408 and catheter 400 into a vein. During normal use of the OTN catheter assembly, the hub 418 of the OTN catheter 400 is coaxially mounted over the nozzle 414 and the hypodermic needle 408 protudes through both the nozzle 414 and OTN catheter 400. The feathered tip 412 of the catheter 400 promotes an easy advance of the catheter 400 over the needle 408. Prior to inserting the needle 408 and catheter tip 412 into a vein, the needle 408 and catheter tip 412 are enclosed by a removable cap (not shown). The needle chamber 402 contains an integral linear track 420 to enable precise axial movement of the needle carrier 406 along the track 420. The needle carrier 406 contains an axial cavity 422 with dimensions that approximately match the dimensions of the linear track 420 in the needle carrier 406 with reasonable play to allow for precise axial movement if the needle carrier 406 along the track 420. In particular, both the cavity 422 and the linear track preferably have trapezoidal, oval, or other non-rotatable cross-sections, and the dimensions of the cavity 422 are slightly greater than the associated dimensions of the linear track 420 (Fig. 8). Thus the linear track 420 stabilizes the needle carrier 406 in relation to the needle chamber 402. Alternatively, the needle carrier 406 may be designed to ride and slide on the inner surface of the needle chamber 402. Forward movement of the needle carrier 406 is limited by its contact with a partition disc 424 which forms the rear wall of the flashback chamber 404. If a flashback chamber 404 is not included in the assembly, forward movement of the needle carrier 406 is limited by its contact with the face plate 428 of the nozzle 414. Rearward movement of the needle carrier 406 is limited by detentes 426, located on the linear track 420, over which the needle carrier 406 is irretrievably locked when retracted. The latch 410 is a ring latch pivotally mounted on a flange 421 of the needle carrier 406, and the latch 410 permits the needle carrier 406 to be locked in either a forward position or a retracted position. Prior to and during normal use of the OTN catheter assembly, the latch 410 retains the hub 418 of the OTN catheter 400 against the face plate 428 of the needle chamber 402 so as to lock the needle carrier 406 in the forward position (Fig. 7). Following puncture of the vein of a patient and insertion of the OTN catheter 400 into the vein, the latch 410 is disengaged from the hub 418 of the OTN chamber 402. The latch 410 is retracted through a longitudinal slot 430 in the needle chamber 402, thereby causing the needle carrier 406 and the mounted needle 408 to be retracted. Retraction of the needle carrier 406 and the needle 408 is complete when detentes 432 on the needle carrier 406 engage the detentes 426 on the linear track 420. At this retracted position the needle carrier 406 is irretrievably locked to the linear track 420 with the needle 408 positioned inside the needle chamber 402 (Fig. 9). The OTN catheter 400 is them dislodged from the nozzle 414 and advanced into the vein. The purpose of the hinge-type latch 410 is to mechanically unify the needle chamber 402 with the needle carrier 406 so that insertion force applied to the needle chamber 402 is directly transmitted to the hypodermic needle 408 and catheter 400. Release of the latch 410 disassociates this mechanical unity, permitting the needle carrier 406 to be retracted within the needle chamber 402 and locked in the retracted position. In an alternative embodiment, similar force transmission and disassociation is achieved using a lever-type latch 438 which engages in a T-shaped slot having proximal and distal transverse portions 440, 442 and a longitudinal portion 444 connected therebetween (Fig. 10-12). The needle carrier 406 is locked in the forward position by engaging the latch 438 in the distal transverse portion 442 of the slot. Disengagement of the latch 438 from the distal transverse portion 442 of the slot permits the latch 438 to slide axially rearward through the longitudinal portion 444 of the slot. Since the needle carrier 406 is attached to the latch 438, rearward axial movement of the latch 438 causes corresponding rearward axial movement of the needle carrier 406. The needle carrier 406 is locked in the retracted position by engaging the latch 438 in the proximal transverse portion of the 440 of the slot. During the puncture of the vein, confirmation that the needle 408 and catheter tip 412 are located in the vein and can be made by viewing blood entering the catheter 400 by capillary action. It, however, is preferable to provide the OTN catheter assembly with the flashback chamber 404 to assure that continuity between the needle 408 and the vein is established. The flashback chamber 404 is incorporated in the OTN catheter assembly by inserting the partition disc 424 just distal to the forward position of the needle carrier 406. The partition disc 424 is retained in the needle chamber 402 by a limit stop 446 extending between the partition disc 424 and the face plate 428. The partition disc 424 has outer dimensions matching the inner dimensions of the needle chamber 402, and the disc 424 has longitudinal openings sized to allow snug passage therethrough of the linear track 420 and the hypodermic needle 408. The hypodermic needle 408 contains a side aperture 434 which opens up into the flashback chamber 404. Confirmation of proper insertion in the vein is indicated by blood entering the flashback chamber 404 via the side aperture 434 in the needle 408. The axial cavity 420 for the linear track 422 vents the flashback chamber 404 to permit this entry of blood into the chamber 404. The OTN catheter assembly is preferably made by a conventional thermoplastic injection molding process. To begin with, the needle chamber 402, including the nozzle 414, body, and linear track 420, are molded as a single unit The partition disc 424 is separated molded from thermoplastic polymer with dimensions which allow the disc 424 to tightly fit within the needle chamber 402. The disc 424 is inserted into the needle chamber 402 to generate the flashback chamber 404. The longitudinal slot 430 is generated by providing an elevation in the mold cavity. Furthermore, while the needle carrier 406 is molded by an injection molding process, the hypodermic needle 408 is insert molded within the needle carrier 406. Alternatively, the hypodermic needle 408 with the side aperture 434 is bonded within the needle carrier 406 after the needle carrier 406 is molded. Next, the needle carrier 406 is inserted into the needle chamber 402, and the molded latch 410 is engaged with the flange 421 of the needle carrier 406. The needle chamber 402 is closed by engaging detentes 436 on the separately molded or integrally molded and folded proximal plate 416 with mating detentes on the needle chamber 402 and the linear track 420. The use the OTN catheter assembly, the skin of a patient is first prepared and a peripheral vein is made prominent. Under aseptic precautions the vein is punctured with the needle 408 and the catheter 400 of the assembly, and the location of the needle tip is judged by the change in color under the catheter or by the appearance of blood in the flashback chamber 404. Once the location of the needle tip is confirmed, the latch 410 is disengaged and slid rearward through the longitudinal slot 430. This action retracts the needle carrier 406 until the detentes 432 on the needle carrier 406 are engaged with the detentes 426 on the linear track 420. While advancing and retaining the OTN catheter 400 in the vein, the remainder of the assembly is removed and an intravenous line is connected to the catheter 400. Finally, the catheter hub 418 is secured to the skin of the patient by adhesive tape. While the present invention has been described with reference to one particular embodiment, those skilled in the art will recognize that many changes may be made thereto without departing from the scope of the present invention. For example, the rotary-type retraction mechanism for the blood sample collection assembly may be replaced with a linear-type mechanism similar to that employed in connection with the OTN catheter assembly. In particular, instead of using the internal tube 320 with the helical slot 324 and the circular knob 322, the needle carrier 308 is provided with an axial cavity that slidably engages a linear track contained in the first needle chamber 302. A latch connected to a needle carrier 308 via a longitudinal slot in the first needle chamber 302 is used to engage the needle carrier 308 in the forward (non-retracted) position. To retract the needle carrier 308, the latch is disengaged and moved longitudinally through the longitudinal slot. Retraction of the needle carrier 308 is complete when detentes on the needle carrier 308 engage mating detentes on the linear track.

Claims: A blood sample collection assembly operable in a normal mode and convertible to a retraction mode, comprising: a first chamber (302) having a longitudinal slot (326); a needle carrier (308) carrying a first hollow needle (310) on the distal end thereof and a second hollow needle (312) being in fluid communication with said first hollow needle (310), said needle carrier (308) being slidably mounted in said first chamber (302), said needle carrier (308) being detachably engaged to said first chamber (302); and retraction means (324,326) for disengaging said needle carrier from said first chamber to switch the assembly from the normal made to the retraction mode and for retracting said needle carrier (308) into the first chamber (302) such that said first needle (310) is concealed within said first chamber (302), characterized in that a vacuum tube chamber (304) is connected to said first chamber (302), and positioned substantially orthogonal to said first chamber (302), said vacuum tube chamber (304) having an open end for receiving a vacuum tube and a second needle chamber (303) opening onto said longitudinal slot (326); said second hollow needle (312) being substantially orthogonal to said first hollow needle (310) and extending into said vacuum tube chamber (304) and whereby on retraction said second hollow needle (310) can pass through said second needle chamber (303). The blood sample collection assembly of claim 1, wherein said retraction means conceals said second needle within said second needle chamber (303). The blood sample collection assembly of claim 1, wherein said retraction means includes retainer means for limiting rotation of said needle carrier (308) relative to said first chamber (302). The blood sample collection assembly of claim 3, the first chamber (302) forming a hollow nozzle (306) located at the distal end of said first chamber and opering into the interior of said first chamber, the distal portion of the needle carrier being engaged within said nozzle during the normal mode and further including a hollow tube (320) rotatably mounted within said first chamber (302), said needle carrier (308) being disposed within said hollow tube. The blood sample collection assembly of claim 4, wherein said retraction means is responsive to rotation of said hollow tube (320) to retract said needle carrier (308) within said hollow tube. The blood sample collection assembly of claim 4, wherein said retraction means includes a helical slot (324) in said hollow tube (320), and wherein said needle carrier (308) includes a side arm (313) extending from said side wall of said needle carrier through said helical slot, said second needle (312) being mounted on said side arm, rotation of said hollow tube relative to said first chamber (302) disengaging said needle carrier from said nozzle (306) of said first chamber and guiding said side arm of said needle carrier proximally through said helical slot, thereby retracting said needle carrier into said hollow tube. The blood sample collection assembly of claim 6, wherein said side arm (313) extends through said helical slot (324) in said hollow tube (320) and said longitudinal slot (326) in said first chamber (302), and wherein rotation of said hollow tube relative to said first chamber guides said side arm proximally through said helical slot and said longitudinal slot, said longitudinal slot preventing said needle carrier (308) from rotating relative to said first chamber (302). The blood sample collection assembly of claim 1, wherein said open end of said vacuum tube chamber (304) includes tabs to facilitate the insertion and removal of the vacuum tube (340). The blood sample collection assembly of claim 1, wherein said second needle (312) includes a self-sealing rubber cap (342) opened by inserting the vacuum tube (340) into said vacuum tube chamber (304) and closed by removing the vacuum tube (340) from said vacuum tube chamber. The blood sample collection assembly of claim 4, further including a knob (322) mounted on the proximal end of said hollow tube (320) to rotate said hollow tube. The blood sample collection assembly of claim 1, wherein said needle carrier (308) includes a tapered male luer (314) at the distal end thereof, and wherein said male luer is detachably engaged within said nozzle (306) by a taper lock. The blood sample collection assembly of claim 6, wherein said hollow tube (320) includes a detent, disposed at the proximal end of said helical slot (324), for engaging said side arm (313) to lock said needle carrier (308) in a retracted position. The blood sample collection assembly of claim 1, wherein said second hollow needle (312) is composed of plastic.

Inventors: MAHURKAR D SAKHARAM, MAHURKAR, D. SAKHARAM
Applicants: MAHURKAR D SAKHARAM, MAHURKAR, D. SAKHARAM
Application year: 1994
Main classification: A61B5
IPC codes: A61B5, A61M5